I installed LMDE a couple of days ago and the only problem I'm having with it right now is that compiz is not working. I have installed a few additional packages from synaptic for all those usual effects that go with the main version of Mint (that I had before overrunning it with Debian edition, and compiz worked there just fine), but nothing seems to be working. Also have Mandriva 2010.1 Gnome on another partition, and compiz works like a charm there. I'm using Radeon 9550 graphic card, without proprietetary drivers (same for all other mentioned systems).